feat: add initial

Signed-off-by: kjuulh <contact@kjuulh.io>

todos/SQ-017-wal-trimming.md

@@ -0,0 +1,27 @@
+# SQ-017: WAL Trimming
+
+**Status:** `[ ] TODO`
+**Blocked by:** SQ-016
+**Priority:** Medium
+
+## Description
+
+Garbage collect local WAL segments after they have been confirmed in object storage.
+
+## Files to Create/Modify
+
+- `crates/sq-storage/src/wal/trimmer.rs` - WalTrimmer
+
+## Behavior
+
+1. Periodically scan for segments marked as "shipped"
+2. Verify the segment exists in object storage (optional double-check)
+3. Delete the local WAL segment file
+4. Update the offset index to point to S3 location instead
+
+## Acceptance Criteria
+
+- [ ] Segment marked as shipped -> trimmer deletes local file
+- [ ] Segment NOT marked as shipped -> trimmer leaves it
+- [ ] After trimming, index entries point to S3 location
+- [ ] Trimmer respects a minimum retention period (keep recent segments locally even if shipped)